Generalization of exotic quark searches

Abstract

General limits on exotic heavy quarks $T$, $B$, and $X$ with masses above 300 GeV are presented for arbitrary branching fractions of $T\ensuremath{\rightarrow}{W}^{+}b$, $T\ensuremath{\rightarrow}Zt$, $T\ensuremath{\rightarrow}Ht$, $B\ensuremath{\rightarrow}{W}^{\ensuremath{-}}t$, $B\ensuremath{\rightarrow}Zb$, $B\ensuremath{\rightarrow}Hb$, and $X\ensuremath{\rightarrow}{W}^{+}t$. The results are based on a CMS search in final states with three isolated leptons ($e$ or $\ensuremath{\mu}$) or two isolated leptons with the same electric charge. Exotic heavy quark pair production through the strong interaction is considered. In the context of vectorlike quark models, $T$ quarks with a mass ${m}_{T}<480\text{ }\text{ }\mathrm{GeV}$ and ${m}_{T}<550\text{ }\text{ }\mathrm{GeV}$ are excluded for weak isospin singlets and doublets, respectively, and $B$ quarks with a mass ${m}_{B}<480\text{ }\text{ }\mathrm{GeV}$ are excluded for singlets, all at a 95% confidence level. Mass limits at the 95% confidence level for $T$ and $B$ singlets, $(T,B)$ doublets, and $(X,T)$ doublets are presented as a function of the corresponding heavy quark masses. For equal mass ${m}_{T}={m}_{B}$ and ${m}_{X}={m}_{T}$, vectorlike quarks are excluded at the 95% confidence level with masses below 550 GeV for $T$ and $B$ singlets, 640 GeV for a $(T,B)$ doublet, and 640 GeV for a $(X,T)$ doublet.